Late queen was not officially told Anthony Blunt was Soviet spy for years

Elizabeth II was not officially informed for almost a decade that one of her most senior courtiers had confessed to being a Soviet spy, according to newly released MI5 files.

Art historian Anthony Blunt was for decades Surveyor of the Queen’s Pictures, overseeing the official Royal Art Collection, and in 1964 admitted he had been a Soviet agent since the 1930s.

Papers released by MI5 show that although Blunt confessed to them he had spied for the Russians during World War Two, the late queen herself was not officially told for nearly nine years.

When she was informed of the full story in the 1970s, she was characteristically unflappable, taking it “all very calmly and without surprise”, according to the declassified files released to the National Archives.

The decision to formally inform the queen came amid growing concerns in Whitehall that the truth would inevitably come out after Blunt, who had been seriously ill with cancer, died. Journalists were already investigating the story and they were no longer constrained by concerns of libel.

Suspicion first fell on Blunt in 1951, after when his fellow spies Guy Burgess and Donald Maclean fled to the Soviet Union.

He had been a close friend of Burgess since their time at Cambridge together in the 1930s – part of the so-called Cambridge Five group of spies.

During World War Two Blunt had worked for MI5, after 1951 he was interviewed 11 times by the Security Service, but always denied espionage.

Then the American Michael Straight told the FBI he’d been recruited by Blunt himself as a Russian agent.

In April 1964 the MI5 interrogator Arthur Martin confronted Blunt, and promised him immunity from prosecution.

His full confession is included for the first time in these files. As well as acknowledging his wartime work, he admitted to being in touch with the Russian Intelligence Service after the war.

Blunt said he met a Russian named Peter before the departure of Burgess and Maclean, but he could not recall exactly why. He said the so-called Peter encouraged him to flee too, but he declined.

The interrogator said Blunt was not “at ease” as he spoke, and every question “was followed by a long pause” while he “seemed to be debating with himself how to answer it”.

Despite Blunt’s prominent position, few outside MI5 were told of this confession. The home secretary and his most senior civil servant were informed.

The queen’s private secretary was told only that Blunt had been implicated and that MI5 intended to interrogate him.

It was agreed that if Blunt became seriously ill, she would be officially informed, because that might prompt press coverage of his past.

In March 1973 another file note records that the queen’s private secretary had spoken to her about the Blunt case. It reads: “She took it all very calmly and without surprise: she remembered that he had been under suspicion way back in the aftermath of the Burgess/Maclean case”.

Miranda Carter, Blunt’s biographer said her “hunch” was Elizabeth II was told informally some time after 1965.

She believes officials “wanted to keep a curtain of plausible deniability”. That the monarch took the news “calmly and without surprise” suggests to Carter that she must have known.

Blunt’s past was finally exposed by Prime Minister Margaret Thatcher in a Commons statement in 1979. He died in 1983 aged 75 having been stripped of his knighthood.

• Cambridge spy Kim Philby declared he would have done it all again after he finally confessed that he had been for years a Russian agent

• Blunt feared that his KGB handler would turn violent when he refused to join his fellow spies Burgess and Maclean and flee to Russia

• Film star Dirk Bogarde was warned by MI5 that he could be the target of a gay “entrapment” attempt by the KGB

• MI5’s top interrogator was baffled by Philby, admitting he could not determine whether he was a Soviet spy

Unlike government departments, MI5 is not subject to the Freedom of Information Act. It releases its archives as it chooses and some files are partially redacted.

Some of the documents released today will feature in a forthcoming exhibition at the National Archives.

The Director General of MI5, Sir Ken McCallum, said: “While much of our work must remain secret, this exhibition reflects our ongoing commitment to being open wherever we can.”